Binding to histo-blood group antigen-expressing bacteria protects human norovirus from acute heat stress.

Dan Li,Adrien Breiman,Mieke Uyttendaele,Jacques Le Pendu

doi:10.3389/fmicb.2015.00659

Abstract

This study aims to investigate if histo-blood group antigen (HBGA) expressing bacteria have any protective role on human norovirus (NoV) from acute heat stress. Eleven bacterial strains were included, belonging to Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Clostridium difficile, Bifidobacterium adolescentis, and B. longum. HBGA expression of the bacteria as well as binding of human NoV virus-like particles (VLPs, GI.1, and GII.4 strains) to the bacteria were detected by flow cytometry. NoV VLPs pre-incubated with HBGA expressing or non-HBGA expressing bacteria were heated and detected by both direct ELISA and porcine gastric mucin-binding assay. The NoV-binding abilities of the bacteria correlated well with their HBGA expression profiles. Two HBGA expressing E. coli (LMG8223 and LFMFP861, both GI.1 and GII.4 binders) and one non-HBGA expressing E. coli (ATCC8739, neither GI.1 nor GII.4 binder) were selected for the heat treatment test with NoV VLPs. Compared with the same cell numbers of non-HBGA expressing E. coli, the presence of HBGA-expressing E. coli could always maintain higher antigen integrity, as well as mucin-binding ability of NoV VLPs of both GI.1 and GII.4 after heat-treatment at 90°C for 2 min. These results indicate that HBGA-expressing bacteria may protect NoVs during the food processing treatments, thereby facilitating their transmission.

Highlights

Noroviruses (NoVs), one genera of the Caliciviridae family, were reported as the cause of between 73% to greater than 95% of global epidemic non-bacterial gastroenteritis outbreaks and approximately half of all gastroenteritis outbreaks (Atmar and Estes, 2006)
histo-blood group antigen (HBGA)-Expression and Human NoV Virus-Like Particles (VLPs)-Binding to the Bacteria Table 1 shows the results of an initial screening of the HBGA expression and NoV VLPs binding ability of the eleven bacterial strains detected by flow cytometry analysis
The qualitative positive results were confirmed repeatedly while the percentage of positively stained cells varied largely probably due to the variation of HBGA expression on bacteria cells from different batches

Summary

Introduction

Noroviruses (NoVs), one genera of the Caliciviridae family, were reported as the cause of between 73% to greater than 95% of global epidemic non-bacterial gastroenteritis outbreaks and approximately half of all gastroenteritis outbreaks (Atmar and Estes, 2006). Human NoVs have been observed to bind to histo-blood group antigens (HBGAs) in a strain-specific manner both in vitro and in vivo (Tan and Jiang, 2010; Ruvoën-Clouet et al, 2013). In the study of Jones et al (2014) B cells were identified as a cellular target of NoVs, and the presence of HBGA expressing enteric bacteria were required for human NoV infection of B cells. Based on these facts, we found it of interest to investigate if the HBGA-expressing bacteria have any protective role on NoV

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